"Distinctive ring" is a service provided by local telephone companies around the world. This feature is also referred to as "Ring Mate", "Identa-Ring", "Ring Master", "Personalized Ring" etc. The distinctive ring service allows a customer to have a single telephone line over which two or more telephone numbers may be accessed. Such access is enabled by the destination telephone or apparatus responding to a distinctive ring cadence associated with a particular one of the telephone numbers. With respect to facsimile machines, the distinctive ring feature enables a programming of the facsimile to recognize only one ring cadence and thus to only answer appropriate calls, i.e., facsimile calls.
Facsimile machines currently being marketed provide menus of different ring cadences from which to choose. These allow a customer to pick from a long ring, two short rings, one short -- one long -- one short ring, etc. Such an implementation has a number of drawbacks. First, facsimile machines cannot be programmed for a ring cadence supplied by the customer's local telephone company but which is not implemented in the facsimile machine. Further, the customer must know something about the facsimile's ring cadence description and match the description to that which is provided by the local telephone company. Finally, because of the many variations in offered distinctive ring cadences, it is difficult to provide a sufficient number of user choices to enable a matching with all such offerings.
For instance, Bell South Services offers a service called "RING MASTER" which provides distinctive ring cadences that are each six seconds in length. The ring cadence may begin at any point in time and consists of 700 to 1,000 ms of ringing, followed by a 350 to 500 ms silent interval, followed by 700 to 1,000 ms of ringing, followed by a 3.5 to 4.25 second silent interval. The ringing pattern may also consist of 400 ms of ringing, followed by a 200 ms silent interval, followed by 400 ms of ringing, followed by a 200 ms silent interval, followed by 800 ms of ringing, followed by a 4 second silent interval.
A similar distinctive ring offering from Bellcore specifies the duration between ring cadences of 3 seconds, with the ring pattern being on-off-on-off-on. The first and third "on" segments are identical in duration and "short" (i.e., 200-500 ms). The second "on" segment is "long" in duration (i.e., 800-1,000 ms). The resulting ring pattern heard by the customer is thus "short-long-short". As is thus obvious, even ring cadences that appear "similar" differ substantially in detail, making it difficult to program a facsimile for many such "similar" offerings.
Telephone companies outside of the United States also offer distinctive ring cadence features, but the cadences are not necessarily identical with U.S.-based offerings. Thus, for products which are pre-programmed to respond to distinctive ring cadences and which are marketed on an international basis, predetermined, fixed cadences do not assure that a product will respond to all ring cadence offerings.
The prior art has approached this problem by attaching a separate controller between devices being called and the PSTN to enable recognition of a distinctive ring signal. In U.S. Pat. No. 5,040,209 to Greenberg et al., a controller is responsive to a number of distinctive ring cadences. The controller includes a number of output ports, each of which is associated with a respective one of the ring-initiating signals and is arranged to have a telephone, fax, answering machine or some other type of device connected to it. The controller, upon detecting a distinctive ring signal, prevents it from reaching all other connected devices and diverts it to just the device to which the ring signal is directed.
Other prior art avoids automatic response to a distinctive ring signal and requires a selection action by the user. For instance, in U.S. Pat. No. 5,086,458 to Bowen, a connection is established with a calling phone and the caller is required to push a key on the touch tone key pad to select a specific extension. A remote unit generates a ringing signal for that extension. In U.S. Pat. No. 5,062,133 to Melrose, a telephone call management system enables a caller to recursively activate a plurality of features, based upon key press inputs. Through one of those inputs, a caller may activate a distinctive ring to provide a special alerting function.
In U.S. Pat. No. 4,910,764 to Bowen, an interface device waits to determine if a tone that is characteristic of a facsimile transmission is heard. If such a tone is detected, the call is connected to a facsimile by a local ring action. If no such tone is detected, the call is connected to a telephone via a local ring action. In each of these systems, additional apparatus is required to enable multiple devices connected to a single telephone line to selectively respond to calls. The addition of such apparatus to control the call routing function adds both expense and complexity to the system.
Accordingly, it is an object of this invention to provide an improved distinctive ring cadence response system to a telecommunications device.
It is a further object of this invention to provide a distinctive ring cadence responsive device which is adaptable to many variations in distinctive ring cadences offered by multiple PSTN's.
It is yet another object of this invention to provide a telecommunications device with a distinctive ring cadence response feature requiring little or no additional equipment.